GB2452578A

GB2452578A - Non-contact actuator

Info

Publication number: GB2452578A
Application number: GB0720900A
Authority: GB
Inventors: Alex Horng; I-Yu Huang
Original assignee: Sunonwealth Electric Machine Industry Co Ltd
Current assignee: Sunonwealth Electric Machine Industry Co Ltd
Priority date: 2007-09-06
Filing date: 2007-10-24
Publication date: 2009-03-11
Also published as: US20090066186A1; FR2918500A1; TW200911676A; JP4657273B2; GB0720900D0; DE102007048592A1; JP2009061575A

Abstract

A non-contact actuator is located on a substrate 10 and includes at least a plate 30 and a bushing 31. When a voltage is applied externally between the actuator and substrate 10, the plate 30 is bent by attraction of the substrate 10 but does not contact the substrate 10. A counteraction force is generated within the plate 30 to withstand the electrostatic force of the substrate 10. After the voltage is removed, the counteraction force and an elastic tension generated by recovering from a curved state of the plate 30 to an original state generate a bouncing motion of the plate 30 and the bushing 31 to produce a step motion or movement of the actuator with respect to the substrate 10.

Description

NON-CONTACT ACTUATOR

[0001] The present invention relates to a non-contact actuator, in which a plate is prevented from contacting a substrate, when the plate is attracted by the substrate, by flexural rigidity of the plate so as to lower friction between the actuator and substrate, reduce the driving voltage and defacement of the device, and prolong the lifespan thereof.

[0002] A known micro fan structure includes micro fan blades produced by a self-assembly technique, and a micro motor comprising a micro-actuator as a rotor, in which the actuation concept of the micro-actuator is illustrated by Fig. 1.

[0003] The micro-actuator structure includes a substrate 10, which is usually a silicon substrate and has a silicon-nitride insulation film with a coating thickness of approximately 0.6 jim thereon; an actuator located on the substrate 10 and having a plate 20 and a bushing 21, in which the plate 20 is parallel to the substrate 10, and the bushing 21 is connected to a front end of the plate 20 so as to be perpendicular to the substrate 10 as shown in Fig. 1(a).

10004] When a capacitive structure is formed by the plate 20 and the bushing 21, an electrostatic force is exerted on the plate 10. Therefore, when a positive bias voltage is applied externally, the plate 20 is attracted by the substrate 10 due to the electrostatic force, such that a rear end of the plate is in contact with the substrate 10 as shown in Fig. 1(b).

[00051 When the positive bias voltage is increased up to a priming voltage, as the friction between the rear end of the plate 20 and the substrate is smaller than that between the bushing 21 and the substrate 10, the plate is bent to cause a large-area contact between its rear end and the substrate and is stored with an elastic tension as shown in Fig. 1(c).

[0006] After the applied voltage is removed, the friction between the rear end of the plate 20 and the substrate 10 is larger than that between the bushing 21 and the substrate 10. As a result, the stored elastic tension is immediately released to drive the actuator to actuate and be displaced as shown in Fig. 1(d).

[0007] When a negative bias voltage is subsequently applied, the plate 20 will also be attracted by the substrate 10 to result in repeated movement, so that the plate 20 is continuously actuated on the substrate 10.

[0008] During the actuation of the actuator, there are two contact surfaces between the actuator and the substrate 10, namely, a contact surface between the rear end of the plate 20 and the substrate 10 and a contact surface between the bushing 21 and the substrate 10. The condition for a actuator to have elastic tension lies in that the positive (or negative) voltage applied between the actuator and the substrate 10 shall be large enough to make the friction between the bushing 21 and the substrate 10 greater than that between the rear end of the plate 20 and the substrate 10. However, such condition inevitably introduces the disadvantages of high driving voltage, high current consumption and defacement of the device.

[00091 In view of the foregoing disadvantages, the present invention thus provides a non-contact actuator that lowers driving voltage, and reduces current consumption and defacement of the device to prolong a lifespan of the actuator.

[0010] Referring to Figure 3, a non-contact actuator of the invention is located on a substrate and at least includes a plate and a bushing.

[0011] When a positive (or negative) bias voltage is externally applied between the actuator and the substrate, the plate is bent by the attraction of the substrate due to an electrostatic force but does not contact the substrate.

Hence, the actuator only has one contact surface between the bushing and the substrate but is free of friction resulting from any contact between the plate and the substrate. The present invention only requires a rather low voltage and consumes a minimum current to provide a bouncing movement arising from the counteraction force generated by the plate itself to withstand the electrostatic force and the elastic tension while the plate recovers from a curved state to its original state.

[0012] The invention will now be described, by way of example, with reference to the accompanying drawings in which: [0013] Fig. 1 is a schematic view showing the movement of a conventional structure; [0014] Fig. 2 is an external schematic view of the non-contact actuator of the present invention; and [0015] Fig. 3 is a schematic view showing the movement of the non-contact actuator of Figure 2.

[0016] In the Figures, like reference numbers denote like parts.

[0017] To make the object, features and efficacy of the present invention more comprehendible, preferred embodiments of the present invention are enumerated along with a detailed illustrative description.

[0018] Referring to Fig. 2, an actuator according to the invention is located on a substrate 10 and includes a plate 30, a bushing 31, at least two support beams 32, at least two sliding seats 33, and at least two rails 34.

[0019] The at least two rails 34 are located on the substrate 10 and are in a straight line pattern or a curved pattern with an equal distance between the rails along their length, such as a pattern of two parallel straight lines or a pattern of two concentric circles.

[00201 The at least two sliding seats 33 are mounted across the aforementioned two rails 34 and have a support beam 32 extending from the respective sliding seats. The at least two support beams are connected to the plate 30 and have chamfers formed at corners intersected by the support beam and each of the sliding seats 33 and the plate 30.

100211 Referring to Fig. 3, the plate 30 is parallel to the substrate 10, and the bushing 31 is connected to a front end of the plate 30 and is perpendicular to the substrate 10 as shown in Fig. 3(a).

[0022J When a positive bias voltage is applied externally, a rear end of the plate 30 is bent by the attraction of the substrate due to electrostatic force but, as shown in Fig. 3(b), does not contact the substrate 10.

[00231 When a positive bias voltage is increased up to a priming voltage, as there is only one contact surface between the bushing 31 and the substrate 10, a rather small voltage is required and a minimum current is consumed to generate a counteraction elastic tension for the plate to withstand the electrostatic force as shown in Fig. 3(c).

[0024J After the applied voltage is removed, the counteraction force stored in the plate 30 and the elastic tension resulted from recovering from a curved state of the plate 30 to its original state are immediately released.

The rebounding force drives the plate 30 and the bushing 31 to bounce and jump, so as to deliver a step motion of the actuator as shown in Fig. 3(d).

[00251 When a negative bias voltage is applied subsequently, likewise, the plate 30 will be attracted by the substrate 10 to generate repeated motion.

As the plate 30 does not contact the substrate 10, the actuator proceeds in continuous motion on the substrate 10.

[00261 When a positive (or negative) bias voltage is applied, the plate is attracted by the substrate 10 due to the effect of an electrostatic force but does not contact the substrate 10. Therefore, a rather small voltage is required and a minimum current is consumed to generate a counteraction elastic tension by using the plate 30 to withstand the electrostatic force. After the applied voltage is removed, the plate 30 still produces the bouncing motion by the rebounding force of the elastic tension stored therein to perform a step movement of the actuator.

[0027] In sum, the present invention provides the aforementioned advantages. From the above-mentioned characteristics those features are not only novel over similar products and have an inventive step but also have industry utility.

[0028] While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention need not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the scope of the appended claims, which are to be accorded with an interpretation so as to encompass all such modifications and similar structures.

Claims

1. A non-contact actuator, located on a substrate and comprising a plate and a bushing, wherein a rear end of said plate is bendable by an attraction of said substrate upon application of a positive (or negative) voltage between said actuator and said substrate but does not contact said substrate, and said actuator moves with a step movement with respect to the substrate due to a rebounding force generated by recovery from a bent state of said plate to an original substantially planar state after removal of said voltage.

2. The non-contact actuator as set forth in claim 1, wherein there are at least two rails disposed on said substrate, sliding seats are disposed across each respective rail, and a support beam extends from each respective sliding seat and is connected with said plate.

3. The non-contact actuator as set forth in claim 2, wherein said at least two rails are either straight or curved and have an equal distance therebetween along their lengths.

4. The non-contact actuator as set forth in claim 2, wherein a chamfer is formed at a corner intersected by said support beam and each of said sliding seat and said plate.

5. A non-contact actuator substantially as described herein with reference to, and as shown in, Figures 2 and 3 of the accompanying drawings.